A common type of electrical connector includes a dielectric housing having a plurality of terminal-receiving cavities within which are mounted a plurality of terminals. The terminals may be stamped and formed metal components and include a mating end for mating with terminals of a complementary electrical connector assembly, along with terminating ends for termination to a plurality of electrical cables, wires or to circuitry on a printed circuit board, for instance. The terminals must be properly positioned within their respective housing cavities for proper mating with the terminals of the complementary connector assembly.
Improper installation of electrical connectors has long been a problem in mating connector assemblies having large numbers of terminals for interconnecting large numbers of electrical circuits. The mating assemblies may perform quite adequately under normal circumstances, but open circuits can occur when the terminals are not properly positioned within the dielectric housings of the connector assemblies or when the assemblies are not properly mated. In addition to open circuits, terminal retention also is important because of problems that can be encountered due to continuous mating and unmating of the connectors over the life of the assemblies. In addition, use of the connectors in vibration environments can cause the terminals to become loosened and improperly positioned. Improper retention of the terminals can result in unstable electrical interconnections.
Various designs have been used to improve the retention of terminals within electrical connector housings and to improve the mating integrity of the connector assemblies themselves. For example, regarding the mating connectors, plastic terminal latches integral with the connector housings often are used to enhance the mating integrity between the connectors. However, regardless of the integrity between the connector housings themselves, if the terminals are improperly positioned, open circuits, terminal damage and other problems can occur even though the connector housings are properly mated. Therefore, various devices have been designed to protect against improperly positioned terminals and, in fact, to prevent the connector assemblies from mating unless all of the terminals therewithin are properly positioned. Such devices commonly have been called "terminal position assurance" devices.
For instance, a known terminal position assurance system in an elongated connector utilizes an elongated terminal position assurance (TPA) member extendable longitudinally through the housing, with the TPA member including a plurality of primary locking devices for retaining the terminals within the connector. Secondary locks on the TPA member are effective to prevent unlocking of the primary locking devices. The connector cannot mate with a complementary connector unless the TPA member is properly positioned. Although this system is quite effective, by providing both the primary locking devices and the secondary locks on the TPA member itself, the system is somewhat complicated and, in some applications, may not be totally cost effective. This invention is directed to an improved system of the character described wherein the primary locking devices are located on the connector housing and the secondary locking devices are located on the TPA member. This system simplifies the TPA member design and provides for more cost effective manufacture of the TPA member and the connector housing.